Continuously varying planetary mechanical transmission system

ABSTRACT

A continuously varying mechanical transmission generally having two sets of planetary gears is disclosed. The transmission of the present invention has a first planetary group generally comprising a control sun, a driven sun and planet gears and a secondary planetary group generally comprising a sun gear, planetary gears and a ring gear arranged and interconnected to provide an easily controllable reduction of ratio between in-lined driving and driven shafts. Each of the planet gears of the first planetary group, being paired and meshed with each other, interact with the control sun and driven sun to permit the reaction forces in all the components to react or rotate simultaneously.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to a continuously varying mechanicaltransmission generally having two sets of planetary gears. Thetransmission of the present invention has a first planetary groupgenerally comprising a control sun, a driven sun and planet gears and asecondary planetary group generally comprising a load gear, planetarygear and a ring gear arranged and interconnected to provide an easilycontrollable reduction of ratio between in-lined driving and drivenshafts. Each of the planet gears of the first planetary group, beingpaired and meshed with each other, interact with the control sun anddriven sun to permit the reaction forces in all the components to reactor rotate simultaneously.

2. Description of the Relevant Art

There has been a substantial need for simplifications and reductions inthe cost in manufacturing and maintaining transmission systems. Fluidtransmissions (as in U.S. Pat. No. 4,213,352 filed by H. Crawford onMar. 14, 1978 and issued July 22, 1980; and in U.S. Pat. No. 4,455,891filed by G. Freeman on Apr. 13, 1981 and issued June 26, 1984) have beendeveloped to provide desirable features. However, fluid transmissionsrequire constant attention and maintenance, especially the need tofrequently adjust and replace brake bands associated with suchtransmissions. More specifically, when used in conventional automobiles,the fluid transmission's torque aversion mechanism is not automaticallyactivated, but require a depression of an accelerator pedal.

The employment of gears of various configurations and arrangements havebeen provided to simplify continuously variable automatic transmissionsas in U.S. Pat. No. 3,015,967 filed on Feb. 8, 1956 by C. Bancroft andissued Jan. 8, 1962; U.S. Pat. No. 3,302,488 filed on Feb. 5, 1963 by F.Graff and issued Feb. 7, 1967; U.S. Pat. No. 3,114,273 filed in May 15,1962 by B. Boggs and issued Dec. 17, 1963; and U.S. Pat. No. 4,327,604filed on Sept. 27, 1979 by R. Evans and issued May 4, 1982. Theabove-mentioned systems are cumbersome in manufacture, maintenance andin operation through the full range of speed reductions required. InU.S. Pat. No. 4,334,440 filed on Mar. 10, 1980 by H. Fouch and issuedJune 13, 1982, a continuously varying transmission which employs threesets of gears is disclosed. Here, a means is provided to hold planetgears of a second set of gears against rotation about a sun gear of thesecond set, but allowing said planet gears to rotate in position. Also,a primary rotary means provides input to a ring gear of the first setwhile a secondary rotary means is connected to planet gears of a thirdset of gears to be rotated and provide output while sun gears of thefirst and third sets are typically interconnected by a shaft extendingthrough a sun gear of the second set.

In the present invention, there is a first planetary group comprising ofat least three pairs of planets connected together by a control carrierstructure operably meshed around control and driven sun gears. Thedriven sun gear interconnects with a ring gear which is part of asecondary planetary set which in turn operably houses a plurality ofplanets, interconnected by a driving carrier structure, meshing andsurrounding a sun gear which is operably joined to a load, driven oroutput shaft. The control and driven sun gears, having equal radiioperably joined to a common axis and spaced-apart in parallel from eachother. A braking control or speed control device gradually locks theplanet control carrier to permit a one-to-one ratio (i.e., wherein thefirst and secondary planetary sets rotate as a single unit) to agradually zero-to-one ratio between the first and secondary planetarysets.

It is therefore an object of the present invention to provide animproved continuously variable mechanical transmission system wherein aload gear operably connected to an output or driven shaft rotates andfollows a rotating control carrier at a continuously and variablyreducing operation.

It is another object of the present invention to provide an improvedcontinuously variable mechanical transmission system wherein therotation or operation of the control carrier is gradually locked byexternally operated brakes, thereby overcoming the locking actionbetween the control carrier and plurality of planet gears to permitreduction of said control carrier and plurality of planet gears at theirdistinct and separate angular velocities relative to their individualaxis, as desired.

It is still another object of the present invention to provide animproved continuously variable mechanical transmission system whereinthe braking device in its simple mechanical operation and constructionbears minimal load sufficient only to overcome the friction between themeshing gears inherent in the operation of the first planetary set.

It is a further object of the present invention to provide an improvedcontinuously variable mechanical transmission system which can be easilyand economically produced, yet sturdy in construction and highlyefficient in operation.

It is a further object of the present invention to provide an improvedcontinuously variable mechanical transmission system which isconstructed with relative simplicity, embodying relatively simple parts,and therefore capable of being retailed for a low price, long-lasting inuse, and extremely convenient to operate.

SUMMARY OF THE INVENTION

The aforementioned and other objects of the present invention areaccomplished by providing a first planetary group, generally comprisinga control sun, a driven sun and a plurality of meshing pairs of planetgears surrounding thereto and a secondary planetary group generallycomprising a load gear, planetary gears and a ring gear operablyconnected to a load, driven or output shaft. A control carrier operablyjoins and surrounds said plurality of meshing pairs of planet gearstherein and a braking control device is communicated thereto for thecontinuous and infinite reduction of angular velocity or rotationthereby accomplishing a similarly continuous and infinite reduction froma one-to-one ratio of a zero-to-one ratio between the first andsecondary planetary sets.

These and other features of the invention will be understood uponreading of the following description along with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the preferred embodiment of acontinuously variable mechanical transmission showing a control carrieroperably surrounding a first planetary set operably coupled to asecondary planetary set which control the output shaft.

FIG. 2 is a top plan view of the first planetary group taken in thedirection of arrows 2--2 shown in FIG. 1 generally showing a controlsun, a driven sun, at least one meshing pair of planet gears, anassociated control carrier coupling and an associated power shaftpassing through a common axis of said suns spaced-apart in parallel fromeach other.

FIG. 3 is a cross-sectional view of the preferred embodiment of thecontinuously variable mechanical transmission taken in the direction ofarrows 3--3 shown in FIG. 1 further illustrating operationalrelationships between the first and secondary planetary sets, theaccompanying connecting operable shafts and transmission casing.

FIG. 4 is a cross-sectional view of the first planetary set, the controlcarrier wheel and the associated braking control device taken in thedirection of arrows 4--4 shown in FIG. 3 illustrating how the controlcarrier surrounds the first planetary set and communicates with thebraking control device.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 is a perspective view of a preferred embodiment of a continuouslyvariable mechanical transmission, generally designated by referencenumber 1, showing a control carrier 3 operably surrounding a firstplanetary set, generally designated by reference number 5, operablycoupled to a secondary planetary set generally designated by referencenumber 8 which control an output shaft 26.

The first planetary set 5 generally comprises at least three pairs ofplanets 10, 11, 12 operably connected by the control carrier 3 andoperably meshed around a control 14 and driven 16 sun gears. A commonaxis communicates through the control 14 and driven 16 sun gears inorder to permit a power shaft 18 to be operably interposed therethrough.Preferably, the control 14 and driven 16 sun gears are of equal radii;although, each preferably having a 10×-tooth and 9×-tooth gear,respectively.

As further shown in FIG. 1, each of the three pairs of planets 10, 11,12, having equal radii, angularly mesh with each other and each planetseparately meshes with its respective abutting control 14 or driven 16sun gear. A 9×-tooth planet preferably meshes with the control sun gear14 while a 10×-tooth planet preferably meshes with the driven sun gear16.

It is further preferred that the control sun gear 14 to the operablyadjoining planets 10, 11, 12 has a rotational ratio of one to one.Moreover, it is preferred that a 3×-tooth driven gear 16 meshes with4×-tooth planets 10, 11, 12.

In the present embodiment of the instant invention, a plurality ofcarrier arms 20 coupled to the control carrier 3 operably secures theappropriate rotation of the pairs of planets 10, 11, 12 around the powershaft. Each carrier arm 20 is operably coupled to each pair of planets10, 11, 12, having an operably coupling means, as will later bediscussed (see FIG. 2), while an opposite end of the carrier arm 20 isattached to a bearing means (not shown here) to permit rotation of thecarrier arms 20, coupled to the control carrier 3, around the powershaft 18, as will later be discussed. Here, the control carrier 3 ispreferably cylindrical to permit complete or substantial housing orenclosure of the first planetary set 12.

Moreover, as shown in FIG. 1, the secondary planetary set 8 generallycomprises a load gear 22, preferably a 19×-tooth gear, central to aplurality of planetary gears 24; each planetary gear 24 preferablyhaving a 31×-tooth type gear. The load gear 22 is directly coupled to aload shaft 26 to stimulate therein the actual rotation of the load gear22. In order to secure the rotating plurality of planetary gears 24around the load gear 22, a driving carrier 75 (not shown) operablycouples to the axis of each of the plurality of planetary gears 24. Thecentral portion of the driving carrier 75 is operably joined at one endof a shaft 28 originating from the power shaft 18 to permit directsimulation by the driving carrier 75 of the actual rotation of the powershaft 18. The load gear 22 and the pluarlity of planetary gears 24operably communicate at meshed gears 30, 32, respectively. Opposingteeth 34 of each of the planetary gears 24 mesh with internal teeth 36of an enclosing ring gear 38 preferably having an 81×-tooth typeinternal gear having an axis operably coupled to a bearing shaft 40which, in turn, is integrally and operably joined with the driven sungear 16 operably integrated within the first planetary set 5.Accordingly, the enclosing ring gear 38 directly simulates the rotationof the driven sun gear 16.

It is preferred that the load gear 22 be equal, in size and number ofteeth, to each of the operably adjoining pairs of planets 10, 11, 12. Itis further preferred that the rotational ratio of the driving carrier 75to the ring gear 38 be three to four for a synchronization of aresulting rotational ratio of three to four in the first planetary set5.

As further shown in FIG. 1, both the power 18 and load 26 shafts areoperably mounted by bearing assisted members 42, 44, respectively to atransmission casing 45. The bearing assisted member 42, 44 arepreferably supported by vertically extending members 47, 49,respectively, integrally bracketed in the upper 52 and bottom 54 wallsof the transmission casing 45.

In order to operably control the rotation of the control carrier 3, atleast one brake pad means internally extends from the upper 52 or bottom54 wall of the transmission casing 45.

As shown in FIG. 2, a top plan view of the first planetary set 5,generally illustrates the control 14 and driven 16 sun gears, at leastone meshing pair of planet gears 10, 11, 12, the associated power shaft18 and the shaft 28 passing through the common axis of the control 14and driven 16 sun gears spaced-apart in parallel from each other, and anassociated control carrier coupling 57 operably joined to a pair ofinternally meshing planets 10, 11, 12 intersecting thereto in beveledgears 60 inherent in each of said meshing planets 10, 11, 12. Thecontrol carrier coupling 57 is operably joined to each meshed planets10, 11, 12 by a generally conventional bearing coupling means 62comprising essentially of a head member 64 abutting an outwardly facemember 65 of the planets 10, 11, 12 having a longitudinal member 68coupled thereto and extending through the axis of the planets 10, 11, 12to permit attachment of the opposite end member 69 to the controlcarrier coupling 57. In order to permit rotation of the planets 10, 11,12 around the longitudinal member 68, conventional ball bearings 70 areaccommodated thereto in spacing 72. Accordingly, the planets 10, 11, 12rotate around the control 14 and driven 16 sun gears at an angle topermit meshing of the planets 10, 11, 12 with each other at contactpoint 73 of beveled gears 60.

In order to properly illustrate the operation of the continuouslyvariable mechanical transmission 1 and to more particularly show theoperational relationship between the first 5 and secondary 8 planetarysets, the accompanying connecting operable output 26 and power 18 shaftsand transmission casing 45, FIG. 3 is shown in a cross-sectional view.Here, power shaft 18 thoroughly extends to a driving carrier 75, beingintegrally joined thereto in order to rotate at the same direction asthe power shaft 18. The accompanying rotation of a plurality of drivingcarrier arms 77 permit the plurality of the planetary set 8 to rotatearound the load gear 22 mounted thereto in load shaft 26. Thus, theopposing reaction from the load shaft 26 subsequently permits rotationof each planetary gear 24 around each driving carrier arms 77 which isattached thereto by conventional bearing means (not shown). The reactionprovided by each rotating planetary gear 24, relative to its axisconnected thereto by bearing means into each carrier arm 77 and relativeto the load gear 22, permits rotation of the ring gear 38 havinginternal threads 36 operably communicating thereto with the planetarygears 24. The reaction executed by the ring gear 38 is operablycommunicated to the driven sun gear 16 of the first planetary set 5operably joined thereto by the bearing shaft 40. A subsequent rotationof the driven sun gear 16 is accordingly achieved to thereby permitrotation therethroughout of the plurality of pairs of planets 10, 11, 12angularly meshed with each other. Upon rotation of the meshing parts ofplanets 10, 11, 12, integrally connected to the control carrier 3 by aplurality of control arms 20, the rotational relationship is alwaysproduced as a one-to-one ratio between the control carrier 3 and theload shaft 26. The control carrier arms 20 are allowed to rotate freelyaround the shaft 28, integral to the power shaft 18, by conventionalbearing loaded means 80. To allow the angular rotation of the controlcarrier 3 and the load shaft 26 to vary in speed, brake pad means 55 orspeed control means (not shown) integrally attached to the casing 45 isperpendicularly exerted toward the control carrier 3; thereby allowingthe rotational motion of the power shaft 18 to surpass the angularrotation of the control carrier 3 (which is equal to the rotation of theload shaft 26) at a proportionate rate relative to the perpendicularforce exerted to the control carrier 3 by the brake pad means 55 orspeed control (not shown).

In order to permit a more efficient meshing between the angled pairs ofplanets 10, 11, 12, equal beveled teeth 83 are provided thereto.Moreover, efficiency in the progressive speed reduction of theabove-mentioned gears of the first 5 planetary set is provided, forexample, by implementation thereto of a 9×-tooth planet meshing with a10×-tooth planet for the pairs of planets 10, 11, 12 of the firstplanetary set 5 at contact points 73; thereby providing a cumulativereduction ratio of 100 to 81. Accordingly, syncronization of therotational parameters between the load gear 22 and control carrier 3,represented herein by the control arms 20 are derived, for example, bythe previously illustrated arrangement; i.e., the rotational ratiobetween the control sun 14 and driven sun 16 of the first planetary set5 is 81 to 100. Similarly, in the secondary planetary set 8, therotational ratio between the driving carrier 75 and the ring gear 38 is81 to 100, as well; thereby, providing a full synchronization betweenthe load gear 22 and the control carrier 3 from zero to full drive, saidload gear 22 and said control carrier 3 having equal rotational speed atall times.

As shown in FIG. 4, the control carrier 3 can alternatively be providedwith an externally protruding flange 85 adaptable for guiding theinternally meshing pairs of planets 10, 11, 12. The flange 85 has apreferable end 87 communicating with a conventional gear bearing means88 to permit the planets 10, 11, 12 to be operably attached thereto androtate therewith. An aperture 90 having a similar plane along a sidemember 92 of the control carrier 3 is provided to permit theaccommodation of the externally protruding end 95 of each of the pairsof planets 10, 11, 12 rotating around the control 14 and driven 16 sunsof the first planetary set 5.

While the invention has been particularly shown and described inreference to preferred embodiments thereof, it will be understood bythose skilled in the art that changes in form and details may be madewithout departing from the spirit and scope of the invention.

I claim:
 1. A continuously varying mechanical transmission, comprising:afirst set of planetary gear means for operably connecting to a powershaft; a secondary set of planetary gear means operably connected tosaid first set of planetary gear means by a bearing shaft for operablyattaching to a load shaft; said first set of planetary gear meanscomprises: (a) a control sun operably coupled to a shaft means forintegrally joining with said power shaft; (b) a driven sun operablycoupled to a shaft means for operably joining with said power shaft,said driven sun is located proximate to said control sun, said drivensun and said control sun are equal in size; (c) a plurality of firstplanet gears suitable for rotating around said control and driven suns,said first planet gears are of equal sizes and are angularly skewed; and(d) a control carrier means for operably joining to said plurality offirst planet gears and at least one brake means exerting towards saidcontrol carrier of said first set of planetary gears to permitcontinuous varying proportion in angular rotation between said powershaft and said load shaft.
 2. The continuously varying mechanicaltransmission as in claim 1 wherein said secondary set of planetary gearmeans comprises:a. a load gear operably coupled to a interconnectingshaft member means for integrally joining with said load shaft; b. aplurality of second planetary gears suitable for rotating around saidload gear; c. a ring gear operably interconnected around said pluralityof planetary gears; and d. a driving carrier operably connected to eachof said planetary gears.
 3. The continuously varying mechanicaltransmission as in claim 2 wherein said plurality of first planet gearsare paired with each other, each pair of first planet gears are angledto permit operable meshing with each other.
 4. The continuously varyingmechanical transmission as in claim 3 wherein said control carrier is acylindrical casing having therein a plurality of carrier arms, eachcarrier arm is operably joined to each said pair of said planet gears.5. The continuously varying mechanical transmission as in claim 4wherein said control carrier is a cylindrical casing having a pluralityof apertures to permit an externally extending portion of said angledplanet gears to freely operate therethrough, each aperture has anextending flange thereover integrally originating from a side of saidcylindrical casing to permit a planet gear to be operably connectedthereto.
 6. The continuously varying mechanical transmission as in claim5 wherein each of said first planet gears has a plurality of bevel gearsintegrally abutting a contacting side of each of said planet gears whichis suitable for meshing.
 7. The continuously varying mechanicaltransmission as in claim 6 wherein said power shaft which is integrallyjoined to a shaft means to permit passing through said control sun andwherein, said control carrier and said driven sun are operably coupledthereto to said load shaft.
 8. The continuously varying mechanicaltransmission as in claim 7 wherein said driven sun is operably connectedto said ring gear of said secondary set of planetary gear means by abearing shaft means.
 9. The continuously varying mechanical transmissionas in claim 8 wherein said driving carrier of said secondary set ofplanetary gear means has a plurality of driving carrier arms, eachdriving carrier arm is operably joined to each of said planetary gearrotating around said load gear.
 10. The continuously varying mechanicaltransmission as in claim 9 further comprising a brake pad meansintegrally attached to a casing of said transmission for operablyimpinging upon said control carrier to permit variable reduction inrotation of said control carrier relative to rotation of said powershaft.
 11. A continuously varying mechanical transmission housed withina casing having protruding therefrom on opposite ends a power shaft anda load shaft, comprising:a. a first set of planetary gears having acontrol sun integrally joined to said power shaft; a driven sun operablycoupled proximately in parallel to said control sun; a plurality ofpaired angularly meshing planet gears; and a control carrier means foroperably joining to said plurality of planet gears, said control sun anddriven sun having equivalent radii, said planet gears having equalradii, said driven sun and said control sun operably joined in parallelby an interconnecting shaft member; and b. a secondary set of planetarygears having a load gear operably coupled to said load shaft beingoperably joined to said first set of planetary gears by a bearing shaft,a plurality of planetary gears altogether joined by a driving carrierhaving a plurality of carrier arms; and a ring gear operablyinterconnected around said plurality of planetary gears and at least onebrake means exerting towards said control carrier of said first set ofplanetary gears to permit continuous varying proportion in angularrotation between said power shaft and said load shaft.
 12. Thecontinuously varying mechanical transmission as in claim 11 wherein saidcontrol carrier is a cylindrical casing having therein a plurality ofcarrier arms, each carrier arm is operably joined to each said pair ofsaid planet gears.
 13. The continuously varying mechanical transmissionas in claim 11 wherein said control carrier is a cylindrical casinghaving a plurality of apertures to permit an externally extendingportion of said angled planet gears to freely operate therethrough, eachaperture has an extending flange thereover integrally originating from aside of said cylindrical casing to permit a planet gear to be operablyconnected thereto.
 14. The continuously varying mechanical transmissionas in claim 12 wherein each of said planet gears has a plurality ofbevel gears integrally abutting a connecting side of each of said firstplanet gears which is suitable for meshing.
 15. The continuously varyingmechanical transmission as in claim 14 wherein said power shaft isintegrally joined to a shaft means to permit passing through saidcontrol sun and wherein, said control carrier and said driven sun areoperably coupled thereto to said load shaft.
 16. The continuouslyvarying mechanical transmission as in claim 15 further comprising abrake pad means integrally attached to a casing of said transmission foroperably impinging upon said control carrier to permit reduction inrotation of said control carrier and rotation of said load gear.
 17. Amethod for continuously varying a control carrier rotational operationequal to a load gear in a mechanical transmission, comprising the stepsof:rotationally operating a power shaft operably interconnected to adriving carrier of a secondary set of planetary gears; rotating aplurality of planetary gears of said secondary set of planetary gearsaround said load gear mounted thereto to a load shaft; rotating eachplanetary gear around each driving carrier arm which is attached theretoby a bearing means, said step of rotating each planetary gear aroundeach driving carrier arm is in the same direction relative to said stepof rotating said plurality of planetary gears of said secondary set;rotating a ring gear in said secondary set of planetary gears havinginternal teeth communicating thereto with said plurality of planetarygears; operably communicating reaction of said ring gear to a driven sunof a first set of planetary gears operably joined thereto by a bearingshaft; rotating a plurality of pairs of planets in said first set ofplanetary gears angularly meshed with each other; rotating a pluralityof control arms thereabout said power shaft; rotating a control carrierin said first set of planetary gears and thereafter, exerting at leastone brake pad toward said control carrier of said first set of planetarygears to permit continuous varying proportion in angular rotationbetween said power shaft and said load shaft.